There is a 2% chance I may be off beam here if my assumptions are wrong, but...
The PINS don't decide Planning Applications; they rule on the validity Planning Decisions taken (or not taken in time) by LPAs by applying Planning Law, Precedent, Policy and Practice.
My initial reaction is that someone has misdirected you in telling you that you can go to Appeal with an amended scheme, which has not been considered by the Council. It can happen but is truly exceptional.
It looks to me that your Appeal has been rejected when the Planning Inspector ran into the first impact of your decision to try and appeal using an amended scheme, which should have gone to the Council and been rejected first before being eligible for Appeal.
Surely by definition you cannot Appeal a decision which has not been allowed to be made?
Unless you meet the conditions for an exception to the rule, which in my opinion would have required expert planning advice.
Whether that can be done is governed by something called the Wheatcroft Principle.
See Section 3.1 and Appendix M of this document:
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/544036/Procedural_Guide_Planning_appeals_v8_0.pdf
And this for an example of how Planning Consultants think they can use (= usually exploit / manipulate) it to get an Appeal by making just enough changes:
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/544036/Procedural_Guide_Planning_appeals_v8_0.pdf
IMO, not having followed normal procedure, your potential claim is likely to be against whoever advised you to Appeal with an altered scheme.
Unless it was a valid exception to the normal process.
Of course, you could use your free resubmission (timescale limit?) as a way to get a new Appeal, but if you do not have the expertise yoruself, get some advice if you have not already done so. A new Planning App refused would be a new Appeal and a new Case.
My sympathy, but you probably tried to use the process in an inappropriate way.
Ferdinand